Control valves are widely utilized in process control loops to regulate transmission and distribution of fluids and gases. These devices are used in a variety of different industries. Valve positioners/controllers are critical control valve system components that have varying degrees of physical integration into the control valve actuator. Many control valves, particularly in more complex systems, include integrated valve positioners. This physical integration, which varies by device manufacturer, includes fixed rigid tubing, hard-wired signal connections, and multi-fastener, multi-tool mounting often with limited or difficult access. Proper physical installation and alignment or removal requires an experienced and trained mechanical technician.
Valve positioners/controllers have grown progressively more technologically sophisticated in recent decades and now require a skilled Electrical and Instrument Technician (EIT) to configure, setup, enter correct identification information, and properly tune the valve positioner/controller. This task often requires the use of specialized equipment and advanced training. It is often manufacturer specific and can be extensive.
Typical positioners provide enhanced control and performance of the valve, and improve the responsiveness of the control valve to changes in process conditions. Unfortunately, however, control valve positioners are subject to failure. Failure of a control valve positioner typically requires that the affected process system be shut down (or at least operated at reduced capacity) to allow for repair or replacement of the control valve positioner. The downtime related to such failures often results in costly production delays.
Moreover, the complexity of a typical control valve positioner makes it impractical or impossible to easily repair or replace a failed device. A typical process plant is unlikely to have qualified technicians on staff able to quickly repair or replace the failed device. It is therefore usually necessary for plant managers to contract for outside specialists to remove the failed positioner, repair the positioner, or install a new replacement positioner, and then configure the reinstalled or newly installed positioner to the particular process settings required by the associated control valve. This amounts to additional downtime costs in addition to the costs associated with contracting the outside specialist labor.
There is thus a long felt and ongoing need in the process control industries for an improved control valve positioner system that minimizes plant downtime and its associated costs.